Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 56799e09 authored by Varun Shah's avatar Varun Shah
Browse files

Add caching to AM.getCurrentUserId(). 

The current foreground user doesn't change outside of a user
switch, which is a rare event on most user devices. Add a
IpcDataCache to AM.getCurrentUserId() in order to avoid
unncessary binder spam.

Flag: backstage_power/android.app.cache_get_current_user_id
Bug: 361853873
Test: atest UserControllerTest
Test: atest UserManagerTest
Test: atest ActivityManagerTest
Test: manually check logs for cache hits/misses
Change-Id: I94540ad4c76bcc62944ad8e19f0e9d6c2154b010
parent 1e2e150c

core/java/android/app/ActivityManager.java

+40 −5
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ import android.os.Bundle; 
import android.os.Debug;

import android.os.Handler;

import android.os.IBinder;

import android.os.IpcDataCache;

import android.os.LocaleList;

import android.os.Parcel;

import android.os.Parcelable;
@@ -237,6 +238,44 @@ public class ActivityManager { 
    private static final RateLimitingCache<List<ProcessErrorStateInfo>> mErrorProcessesCache =

            new RateLimitingCache<>(10, 2);



    /**

     * Query handler for mGetCurrentUserIdCache - returns a cached value of the current foreground

     * user id if the backstage_power/android.app.cache_get_current_user_id flag is enabled.

     */

    private static final IpcDataCache.QueryHandler<Void, Integer> mGetCurrentUserIdQuery =

            new IpcDataCache.QueryHandler<>() {

                @Override

                public Integer apply(Void query) {

                    try {

                        return getService().getCurrentUserId();

                    } catch (RemoteException e) {

                        throw e.rethrowFromSystemServer();

                    }

                }



                @Override

                public boolean shouldBypassCache(Void query) {

                    // If the flag to enable the new caching behavior is off, bypass the cache.

                    return !Flags.cacheGetCurrentUserId();

                }

            };



    /** A cache which maintains the current foreground user id. */

    private static final IpcDataCache<Void, Integer> mGetCurrentUserIdCache =

            new IpcDataCache<>(1, IpcDataCache.MODULE_SYSTEM,

                    /* api= */ "getCurrentUserId", /* cacheName= */ "CurrentUserIdCache",

                    mGetCurrentUserIdQuery);



    /**

     * The current foreground user has changed - invalidate the cache. Currently only called from

     * UserController when a user switch occurs.

     * @hide

     */

    public static void invalidateGetCurrentUserIdCache() {

        IpcDataCache.invalidateCache(

                IpcDataCache.MODULE_SYSTEM, /* api= */ "getCurrentUserId");

    }



    /**

     * Map of callbacks that have registered for {@link UidFrozenStateChanged} events.

     * Will be called when a Uid has become frozen or unfrozen.
@@ -5244,11 +5283,7 @@ public class ActivityManager { 
    })

    @android.ravenwood.annotation.RavenwoodReplace

    public static int getCurrentUser() {

        try {

            return getService().getCurrentUserId();

        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        }

        return mGetCurrentUserIdCache.query(null);

    }



    /** @hide */

core/java/android/app/activity_manager.aconfig

+10 −0
Original line number Diff line number Diff line
@@ -104,3 +104,13 @@ flag { 
     }

}



flag {

     namespace: "backstage_power"

     name: "cache_get_current_user_id"

     description: "Add caching for getCurrentUserId"

     is_fixed_read_only: true

     bug: "361853873"

     metadata {

         purpose: PURPOSE_BUGFIX

     }

}

services/core/java/com/android/server/am/UserController.java

+9 −0
Original line number Diff line number Diff line
@@ -1978,6 +1978,7 @@ class UserController implements Handler.Callback { 
                boolean userSwitchUiEnabled;

                synchronized (mLock) {

                    mCurrentUserId = userId;

                    ActivityManager.invalidateGetCurrentUserIdCache();

                    userSwitchUiEnabled = mUserSwitchUiEnabled;

                }

                mInjector.updateUserConfiguration();
@@ -2239,6 +2240,7 @@ class UserController implements Handler.Callback { 
                return true;

            }

            mTargetUserId = targetUserId;

            ActivityManager.invalidateGetCurrentUserIdCache();

            userSwitchUiEnabled = mUserSwitchUiEnabled;

        }

        if (userSwitchUiEnabled) {
@@ -2316,6 +2318,7 @@ class UserController implements Handler.Callback { 
        synchronized (mLock) {

            nextUserId = ObjectUtils.getOrElse(mPendingTargetUserIds.poll(), UserHandle.USER_NULL);

            mTargetUserId = UserHandle.USER_NULL;

            ActivityManager.invalidateGetCurrentUserIdCache();

        }

        if (nextUserId != UserHandle.USER_NULL) {

            switchUser(nextUserId);
@@ -3021,6 +3024,9 @@ class UserController implements Handler.Callback { 
        mInjector.getUserManagerInternal().addUserLifecycleListener(mUserLifecycleListener);

        updateProfileRelatedCaches();

        mInjector.reportCurWakefulnessUsageEvent();



        // IpcDataCache must be invalidated before it starts caching.

        ActivityManager.invalidateGetCurrentUserIdCache();

    }



    // TODO(b/266158156): remove this method if initial system user boot logic is refactored?
@@ -3184,6 +3190,9 @@ class UserController implements Handler.Callback { 


    @GuardedBy("mLock")

    private int getCurrentOrTargetUserIdLU() {

        // Note: this result is currently cached by ActivityManager.getCurrentUser() - changes to

        // the logic here may require updating how the cache is invalidated.

        // See ActivityManager.invalidateGetCurrentUserIdCache() for more details.

        return mTargetUserId != UserHandle.USER_NULL ? mTargetUserId : mCurrentUserId;

    }

services/tests/servicestests/src/com/android/server/am/UserControllerTest.java

+4 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ import android.os.Bundle; 
import android.os.Handler;

import android.os.HandlerThread;

import android.os.IRemoteCallback;

import android.os.IpcDataCache;

import android.os.Looper;

import android.os.Message;

import android.os.PowerManagerInternal;
@@ -197,6 +198,9 @@ public class UserControllerTest { 
    @Before

    public void setUp() throws Exception {

        runWithDexmakerShareClassLoader(() -> {

            // Disable binder caches in this process.

            IpcDataCache.disableForTestMode();



            mInjector = spy(new TestInjector(getInstrumentation().getTargetContext()));

            doNothing().when(mInjector).clearAllLockedTasks(anyString());

            doNothing().when(mInjector).startHomeActivity(anyInt(), anyString());

services/tests/servicestests/src/com/android/server/pm/UserManagerTest.java

+4 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ import android.content.pm.UserProperties; 
import android.content.res.Resources;

import android.graphics.drawable.Drawable;

import android.os.Bundle;

import android.os.IpcDataCache;

import android.os.PersistableBundle;

import android.os.UserHandle;

import android.os.UserManager;
@@ -100,6 +101,9 @@ public final class UserManagerTest { 


    @Before

    public void setUp() throws Exception {

        // Disable binder caches in this process.

        IpcDataCache.disableForTestMode();



        mOriginalCurrentUserId = ActivityManager.getCurrentUser();

        mUserManager = UserManager.get(mContext);

        mActivityManager = mContext.getSystemService(ActivityManager.class);